Sheet separating device



Sept. 25, 1951 I G. R. ROBINSON SHEET SEPARATING DEVICE Filed JanPatented Sept. 25, 1951 SHEET SEPARATING DEVICE Grant R. Robinson,Melrose, Mass., assignor, by direct and mesne assignments, to Old TownRibbon & Carbon 00., Inc. of Mass., a corporation of MassachusettsApplication January 17, 1946, Serial No. 641,686

Claims.

Thi invention relates to sheet feeding devices and more particularly toinstrumentalities for causing a single sheet to be separated from thestack in preparation for being operated upon by other mechanism orinstrumentalities.

In the art, it is recognized that the separating of a single sheet froma stack of sheets presents a problem due to the characteristics inherentin the sheets themselves such as, for example, thickness and surfacefinishes. Also, the conveniently termed static condition that isoccasioned or developed between sheets in a stack formation and has atendency to cause the sheets to adhere to one another and furthercomplicates the separation of a single sheet.

It is further known in the art that many complicated mechanisms havebeen devised to effect the separating of a sheet from a stack so thatthe sheet may be singly advanced to be further operated upon. Many suchdevices employ suction elements adapted to be engaged with the face ofthe outermost sheet of the stack and, through means of suction, singlyseparate this sheet for advancement.

Mechanical structures have been utilized for the purpose of separatingan outermost sheet from a stack so that the sheet may be singlyadvanced. Generally stated, the presently known mechanical separatingdevices require a complicated structure embodying various adjustments topermit of its use in connection with the range of conditions andproblems presented. Such mechanical structures have also included a stopwhich engages with the forward or advance end of the stack. Stops ofthis character have heretofore been provided with a spring pressedflange portion which overlies and engages a margin of the uppermostsheet of the stack under pressure and, as the stack is decreased, theflange follows the lowering of the stack plane.

Other such devices employ a single stop disposed at right angles to theface plane of the stack and adapted to engage with a portion of theforward end and face plane of the stack. Stops of this character aredependent on gravity to cause the stop to adjust itself as the height ofthe stack decreases. This presents a problem as the pressure of thestack end against the stop may be in varying degrees and sufficient toprevent the proper adjustment of the stop by itself.

Accordingly, one of the primary objects of the present invention is toprovide a sheet separating device of a simple construction and soarranged that the pressure of the advance stack end aids in the properfunctioning of the device.

Another object of the invention is to provide a sheet separating devicethat is so constructed and arranged that as the uppermost sheet isadvanced from the stack it will facilitate separation of the sheet fromthe stack and effect urging of the sheet separating device in its properfunctioning direction.

A further object of the invention is to provide an automaticallyadjusting means that is simple in construction with a minimum of workingparts that may be readily assembled and easy and convenient to operate.

The foregoing objects are intended as a general explanation and are notto be construed as limiting the invention thereto as other objects andadvantages will become apparent from the following detailed description.

The accompanying drawing illustrates a preferred form of the inventionassociated with a duplicating machine sufificient to enable thoseskilled in the art to understand the construction and operation thereof.

Referring to the drawing:

Fig. 1 is a sectional elevation of a portion of a duplicating machineand sheet feeding device having the present invention embodiedtherewith.

Fig. 2 is a side elevation of the sheet separating device and a stack ofsheets being positioned for feeding to other advancing or operatinginstrumentalities.

Fig. 3 is a view corresponding substantially to Fig. 2 but shows theparts in a different position.

Fig. 4 is a plan view of the stack abutment stop and sheet separatingdevice.

Fig. 5 is an end elevation of the device as shown in Fig. 4, and

Fig. 6 is a section taken substantially along line 6-6, Fig. 4, butshows a modified form of face for the abutment of the sheet stackadvance end.

Fig. '7 is a fragmentary view illustrating a feature of the invention.

While not limited thereto a practical embodiment of the presentinvention is combined with a so-called fluid process duplicating machinehaving opposed side frames ll, only one of which is shown, thatrotatably supports a master carrying or printing drum l2 and a coactingpressure roll [3. The machine is provided with a support It adapted toreceive and support a stack of sheets l5. Sheets are to be singly fedfrom the stack by a suitable sheet engaging de- When a sheet is advancedfrom the stack l its forward end is engaged by a pair of rolls 22; 23,which are also operated in a timed relation to the drum [2, and advancedto engage in the bite, formed by the drum [2 and its coaotin'g pressureroll, to be further operated upon as the drum I2 is rotated.

As the sheet is advanced by the rolls 22, 23 the upper face of the sheetis moistened by means of moisture that is first applied to the face ofthe roll 22 by a suitable fluid applicator 34.

As is well known in the art, a pack or stack of sheets is generallyremoved from their container or handled in a uniform block formationwhich presents many problems in feeding sheets singly from the block.some of these problems'may be stated as being directly or indirectlyoccasioned by varying characteristics inherent in the sheets themselvessuch as, for example, thickness and surface finishes. Also; the staticcondition impedes the simple and convenient separation of a single sheetfrom the stack. A further problem is presented in the fact that, assheets are removed from the stack, the height of the stack iscontinuously diminished.

I have found that various difficulties in separating a sheet singly froma stack requires consideration of the position and form of the stack,its relation to the point to which the sheets are to be delivered, and apivot point around which a desirable sheet separating device is arrangedto move.

The foregoing factors have been successfully determined in the mechanismnew to" be described. An arm 2 is pivoted at 25 to a stationary portionof the machine frame below the stack support It. The front end of thisarm is provided with a transversely or laterally extending narrow stop26 that, when the arm 24 is in a normal operative position as shown inFig. l, is disposed at an angle to the plane of the stack support It andconstitutes a stop for the advanced edge of the stack of sheets E5. Theinner stack-engaging face Zi a of the stop 25 is provided at its upperedge with a' V-shape'd' projection or' lip 21 that is preferablydisposed at an angle somewhat greater than a right angle to the stopface Zfia, and this lip ZI'is located over a forward corner area of thestack !5. As illustrated in Fig. 6, the lip 2'. is disposed at an angleof about to the inner'face of the" stop member 26.

In operation the arm 24 may be rocked upwardly to an inoperativeposition by a finger tab 23 projecting upwardly therefrom and a stackit) of sheets placed on the stack support [4. The stack may then befeathered against the stop face 23a and the stop accurately positioned"with its prof g lip 2? in engagement withthe uhpermost at of the stack.the stop 25a is shown'as straight but inclined although theoreticaily,to'permit the arm 24 properly to rock about its pivot 25, the stop faceshouid be arcuate inform as indicated at 2%?) as inFig. Howeveifl-ithas'beenfoun'd that In Figs. 1 and 2 a straight face 26a will functionin a satisfactory manner.

A stack-engaging wall 30 extends upwardly from one side of the stacksupport l4 and the arm slides in engagement with the outer face of thiswall. As illustrated in Fig. 4, the stop 28 efrteiids'latrally about thefront end of the wall 39 and is provided with the rearwardly extendinglip 2! at its upper marginal edge. One edge of the lip 21 extendsrearwardly along and adjacent to the wall 30 to a sharp point 32 asindicated in Fig. 4, and the other edge 34 of the lip extends. obliquelyforwardly and outwardly from the wall 3|].

The stack 15' ofsheets is aligned with one side against the wall 39 andwith its forward edge in engagement with the stop 25. The latter is heldin suspended position by the lip 21 resting on the top of the stack. Asthe carriage 16 moves forwardly, the elements I! force the top sheetforwardly against the stop whereupon the sheet buckles as shown in Fig.3. The angleof the lip 21 is such that upon buckling the edge of thesheet comes in contact with the oblique marginal edge 36 of the lip 27and rides along that edge until it is disengaged from the stop and lipwhereupon its advancing edge passes over the stop and is directed to thebite of the feed rolls 22 and 23. The buckling separates the top sheetfrom the stack, andwhen the sheet is thus separated the air entrappedbeneath it aids to break vacuum attachment between the sheets and tofree the top sheet for forward movement.

As the height of the stack l5 of sheets is decreased the arm 2!; rocksdownwardly, its stop face being always gauged as to level and maintainedat the proper height for the stack by the engagement of the lip 2! withthe uppermost sheet of the stack. It is pointed out that forwardpressure of the stack of sheets, and of the top sheet, against the stop26'not only does not obstruct downward movement of the pivoted arm 24but aids gravity by urging such downward movement and so maintains thestop in position with its lip 2'! in contact with the top of the stack.Since'the pivot-25 is disposed below the support l4, forward pressure ofthe stack against the stop 28 eiierts both forward and downward pressureon the pivoted arm Q4 of the stop as indicated by the lines F in Fig. 7.I 7

From the foregoing illustrations and descrip tions itis apparent thatmany modifications and adaptations may be effected with the presentdisclosure by those skilled in the art without departing from the spiritand scope of the invention; therefore I do not wish to be limitedto thespecific details and arrangement of parts" herein disclosed.

what I claims is:

1. In a sheet feeding device, the combination of a substantiallyhorizontal support for a stack of sheets, means for feeding the topsheet forwardly from the stack and support, a movable member having anarrow upright stack-engaging stop at one corner of the support locatedfor wardly of one side thereof and pivoted for vertical movement about ahorizontal axis disposed rearwardly of the stop and belowthe support,and a rearwardly extending lip on the upper portion of the stop inposition to rest on the top sheet of a stack engaged against the stop.

2. The combination defined in claim" 1 in which said stack-engaging stopslopes rearwardly from the bottom'to the top thereof. W

3. The combination defined in' laim 2 iii which the angle between thestop and lip approximates 115.

4. In a sheet feeding device, the combination the front end of and for alimited distance from 0 the wall to a position providing at a corner ofthe support a stop forwardly of the said one side thereof for engaging astack of sheets in contact with the wall, a rearwardly extending lip onthe upper portion of the stop in position to rest on the adjacentforward corner of the top sheet of the stack, and means pivoting the armfor vertical movement about a horizontal axis disposed rearwardly of thestop and below the support.

5. The combination defined in claim 4 in which said lip has one edgeextending rearward- 6 1y along and substantially parallel with the wallto a point adjacent to the inner face of the wall and another edgeextending obliquely from said point forwardly and away from the wall tothe stop.

GRANT R. ROBINSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 825,186 Brown July '3, 1906 151,025,282 Lev May '7, 1912 2,022,365 Ackerman et al. Nov. 26, 19352,166,272 Storck July 18, 1939 FOREIGN PATENTS 20 Number Country Date335,765 Germany Apr. 9, 1921

